Combined check valve and strainer unit for fuel pumps



Jan. 5, 1965 w. A. BRADLEY 3,164,168

COMBINED CHECK VALVE AND STRAINER UNIT FOR FUEL PUMPS Filed July 12, 1961 F I G. l

24 H I I 29 2e 4 3 3 22 1 F l G. 2 2/ INVENTOR. WILLIAM A. BRADLEY United States Patent 3,164,168 CQMEINEI) CHEQK VALVE AND STRAENER UNIT FUR FUEL PUMP? William A. Bradley, University City, Mo, asssgnor to ACE Industries, Incorporated, New York, N.Y., a corporatiou of New Jersey Filed duly 12, 1961, Ser. No. 123,572 9 tliaims. 8i. 137-544) This invention relates to fuel pumps and particularly to a constant pressure variable volume diaphragm type pump adapted to supply fuel to an engine in sufficient quantities to satisfy engine requirements.

In fuel systems embody-ing a carburetor provided with a float cont-rolled needle valve to maintain fuel at a predetermined level within a fuel bowl, a particle of dirt or metal may become engaged between the needle and its seat and thereby prevent closing of the valve by the float after the fuel has reached its predetermined operating level within the fuel bowl and thereby cause flooding of the carburetor. To prevent the occurrence of such a condition, it is necessary to provide means to separate dirt or metal particles from the fuel before it is delivered to the carburetor.

It is, therefore, an object of the invention to provide for a fuel pump a novel strainer unit to separate particles of dirt or metal from the fuel prior to discharge of the fuel from the pump.

A further object of the invention resides in the provision of a novel combined check valve and strainer unit which is relatively simple and inexpensive in construction and adapted to be press-fitted into a fuel inlet or outlet chamber during assembly of a fuel pump.

The invention embodies other novel features, details of construct-ion and arrangement of parts which are hereinafter set forth in the specification and claims and illustrated in the accompanying drawings, forming part thereof, wherein:

FIG. 1 is a side elevation illustrating a fuel system for an internal combustion engine.

FIG. 2 is a vertical section illustrating a diaphragm fuel pumps embodying features of the invention.

FIG. 3 is a section taken along the line 33 of FIG. 2.

FIG. 4 is an enlarged sectional view illustrating the combined check valve and strainer structure.

Referring now to the drawings for a better understanding of the invention and particularly to FIG. 1, a conventional fuel system for an internal combustion engine 2 is shown as comprising a carburetor 3 mounted on the intake manifold 4 and supplied with fuel from a tank 6 through a conduit 7 by means of an engine driven fuel pump 3. As shown in FIG. 2, the fuel pump 8 is detachably mounted on the engine by any appropriate means and is actuated by a cam 9 on an engine driven cam shaft 11.

The fuel pump 8 is shown as comprising a rocker arm 12 pivotally mounted intermediate its ends on a pin 13, which is mounted at its ends in a rocker arm housing 14. The outer end of the rocker arm 12 is maintained in frictional engagement against the cam 9 by means of a compression spring 16 fitted between the housing 14 and rocker arm 12. The inner end of the arm 12 is bifurcated at 15 to receive the lower end ltl of a pull rod 17 having washers 18 thereon for engagement by the lever 12. The pull rod 17 extends upwardly through an oil sealing washer 19 into a spring chamber 21 and has its upper end secured to a flexiblepurnp diaphragm 22. A helical compression spring 23 encircles the pull rod 17 and is, seated between the outer periphery of the oil sealing Washer lg and a diaphragm backing plate Zfl to yieldably resist donward movement of the diaphragm 22.

A pump casing 24 is shown as blanked and formed from sheet metal to provide a pump chamber 26 in communication with thefuel inlet and outlet chambers 27 and 28. The casing 24 is also formed With an annular downwardly extending flange 29 which is turned inwardly at 31 during assembly to clamp the outer peripheral portion of the diaphragm 22 against the upper surface of an annular flange 32 formed on the upper end of the rocker arm housing 14. Pipe nipples 33 and 34 are provided on the pump casing 24 for the attachment of the conduit 7 to deliver fuel into and out of the chambers 27 and 28, respectively. The side walls 36 and 37, respectively, of the chambers 27 and 28 are substantially cylindrical but may be of gradually decreasing diameter from the pump chamber 22 upwardly toward the pipe nipples to facilitate fabrication of the casing and the assembly of the check valve assembly units 38 therein. The features of pump casing 24 are disclosed and claimed in the copending application of Russell F. Smith, et al., Serial No. 122,025, filed July 5, 1961. V 7 As illustrated in FIG. 2, the fuel inlet and outlet ohambers 27 and28 are each provided with a combined check valve and strainer assembly unit 38 arranged to cause a flow of fuel from the tank 6 to the carburetor 3 responsive to reciprocative movement of the pump diaphragm 22. It will be noted that the check valve unit 38 in the fuel inlet chamber permits fuel flow in one direction from the fuel inlet chamber 27 into the pump chamber 26, and that the check valve unit 38 in the fuel outlet chamber 28 permits fuel flow in one direction from the pump chamber 26 through the outlet nipple 34 and conduit 7 to the carburetor 3.

The combined check valve and strainer unit 38 is shown in FIG. 4 as comprising a valve cage 39 provided with a valve seat 41 blanked and formed from sheet metal. The seat ll. is formed with a central opening 42 defined by an inner peripheral flange 43 adapted to tightly receive and engage a valve guide stem 44 of a valve retainer 46. The seat 41 is also formed with an outer peripheral flange 47 concentric with the inner flange 43 for press-fit engagement with the walls 360! 37 of the fuel inlet and outlet chambers 27 and 28, respectively. A ring of circumferentially spaced ports 48 are provided in the seat 41 concentric with the flanges 43 and 47.

The valve retainer 46 is shown as blanked and formed from sheet metal to provide an annular valve stop 49 integral with and joined to the hollow valve stem 44 by means of aspring seat portion 50 and circumferentially spaced struts 51. The retainerdd is also formed with an end wall 52 adapted to be deformed during assembly to anchor the stem 44 on the valve seat 41, as illustrated in FIG. 4. 1

A flat disk valve 53 formed of resilient synthetic rubber or plastic is provided with a central aperture to slidably engage the valve stem 4-4 and to engage the valve seat 41 to close the ports 48 to fuel flow in one direction. A helical compression spring 54 is mounted on the stem 44 to engage and bias the disk valve against its seat.

A strainer 56 blanked and formed of resilient sheet material, such as woven wire, is provided with a central aperture to receive a tubular sheet metal eyelet 57 which, during assembly, is press-fitted into the steam 44 and flared outwardly at 58 to provide an annular flange to clamp the inner peripheral portion of the strainer against the upperannular surface of the valve stem 44. If desired, the annular flange 58 may be formed on the eyelet prior to assembly. The strainer is formed with an arcuate body portion 59, having its concave side facing the valve seat 41, the marginal portion of the strainer being formed to provide an annular flange 61 extending away from the valve'seat.

During assembly, the flange 61 is press-fitted chambers 27 or 28.

In the operation of the pump thus shown and described, the earn 9 first acts through the rocker arm 12 and pull rod 17 to move the diaphragm 22 downwardly to draw fuel from the tank'n past the inlet check valve 38 into the pump chamber 26 and to load spring 23. The spring 23 then acts to move the diaphragm 22 upwardly to force fuel from the pump chamber 26 past the outlet check valve 38 to the carburetor 3. During operation of the pump, all fuel flow through the pump passes through the inlet and outlet strainers 56, so that particles of dirt or metal carried by the fuel are separated from the fuel by the strainer 56.

While the invention has been shown in but one form, it will be obvious to those skilled in the art that it is not so limited but is susceptible of various changes and modifications Without departing from the spirit of the invention or the scope of the depending claims.

I claim: 7

1. A combined check valve and strainer unit for a fuel pump having a cylindrical fuel passage in communication with a pumping chamber, said unit comprising a valve cage including a valve seat adapted to be mounted in said fuel chamber, said valve seat being provided with a central aperture and a port radially spaced from said aperture, a valve retainer including a tubular stem having one end mounted in and closing said central seat aperture and an annular spring seat portion on the other end of said stem, a disk valve slidably mounted on said stem and closing said port, a compression spring engaged between said spring seat portion and said disk valve, an annular strainer fitted 'coaxially on said other stem end, said strainer having an outer peripheral flange adapted to engage the cylindrical fuel passage, and a tubular eyelet press-fitted into said stem and clamping the inner peripheral portion of said strainer against said spring seat portion.

2. A combined check valve and strainer unit comprising a valve seat structure having a fuel passage therethrough, a retainer fixed to said valve seat structure and having a closed tubular stem provided with a free end having a spring seat portion, a valve mountedfor'movement on said stem, a spring between said valve and said spring seat portion urging said valve onto said valve seat structure, to close said fuel passage, a strainer on said free stem end, and a member extending through said strainer into said stem and clamping said strainer against said spring seat'portion.

3. The invention of claim 2 wherein said member is tubular and is in press-fit engagement in said stem.

4. The invention of claim 3 including said strainer being formed of resilient material and having an outer peripheral circular flange adapted to fit across a cylindrical fuel passage. i

5. A check valve assembly for a fuel pump, said valve assembly comprising a valve cage formed with a ported valve seat surface and a central opening, a valve retainer including a tubular stem having one end fixed within said central opening, said tubular retainerstem having a spring seat portion at the other end thereof, a disk valve slidably mounted on said stem, a coil spring mounted around said stern between said spring seat portion and said disk valve and biasing said disk valve against said ported valve seat surface, a mesh strainer having a central opening, and a tubular eyelet press-fitted through said central strainer opening and into said stem at its other end, said eyelet having a flanged portion clamping the inner peripheral portion of said strainer against said other stem end.

6. A .check valve assembly for a fuel pump, said valve assembly comprising a valve cage formed with a ported valve seat surface and a flanged central opening, a valve retainer including a hollow tubular stem having one end fixed Within said flanged opening, said tubular retainer all stem having a spring seat portion at the other end thereof, a disk valve slidably mounted on said stem, a coil spring mounted around said stem between said spring seat portion and said disk "alve and biasing said disk valve against said ported valve seat surface, a metallic mesh strainer of arcuate form and having a central opening, and a tubular eyelet press-fitted through said central strainer opening and into said stem at its other end, said eyelet having a flanged portion clamping the inner peripheral portion of said strainer against said other stem end, said strainer extending over said disk valve and valve seat portion.

7. A check valve assembly for fitting into a tubular passage of a fuel pump, said valve assembly comprising a circular valve cage adapted to be press-fitted into said tubular pump passage, said valve cage formed With a ported valve seat surface and a flanged central opening, a valve retainer including a tubular stem having one end fixed Within said flanged opening, said tubular retainer stem having a spring seat portion at the other end thereof, a disk valve slidably mounted on said stem, a coil spring mounted around said stem between said spring seat portion and said disk valve and biasing said disk valve against said ported valve seat surface, a circular metallic mesh strainer of arcuate form having a central opening and adapted to be press-fitted into said tubular pump passage, and a tubular eyelet press-fitted through said central strainer opening and into said stem at its other end and having a flanged portion clamping the inner peripheral portion of said strainer against said other stem end.

8. A check valve assembly for a fuel pump, said valve assembly comprising a valve cage formed with a. ported valve seat surface and a flanged central opening, a valve retainer including a hollow tubular stem having one end end fixed within said flanged opening, said tubular retainer stern having a spring seat portion at the other end thereof, a disk valve slidably mounted on said stern, a coil spring mounted around said stem between said spring seat portion and said disk valve and biasing said disk valve against said ported valve seat surface, a metallic mesh strainer of arcuate form and having a central opening, and a tubular eyelet press-fitted through said central strainer opening and into said stem at its other end, said eyelet having a flanged portion clamping the inner peripheral portion of said strainer against said other stem end, said strainer extending over said disk valve and valve seat portion, said circular strainer being spaced from and extending over said valve disk and valve seat surface.

9. A combined check valve and strainer unit comprising a valve retainer having a tubular stem provided at one end with an annular spring seat portion, a strainer having a central opening, a member extending through said strainer opening into said stem clamping said strainer against said spring seat portion, a disk valve slidably mounted on said stem, and a valve seat having a part therethrough secured to the other end of said stem, a spring between said spring seat port-ion and said disk yalve urging said disk valve against said valve seat to close said port, said seat having an inner annular peripheral flange in press-fit engagement with said stern, said strainer and seat having outer annular peripheral flanges.

References Qited in the file of this patent UNITED STATES PATENTS 2,617,535 Hamilton Nov. 11, 1952 2,625,114 Cotfey Jan. 13, 1953 2,731,033 Cable Jan. 17, 1956 2,803,265 Coffey Aug. 20, 1957 2,832,295 Waldherr Apr. 29, 1958 2,844,164 Robbins July 22, 1958 2,929,333 Harry Mar. 22, 1960 FOREIGN PATENTS 621,906 Canada June 13, 1961 

1. A COMBINED CHECK VALVE AND STRAINER UNIT FOR A FUEL PUMP HAVING A CYLINDRICAL FUEL PASSAGE IN COMMUNICATION WITH A PUMPING CHAMBER, SAID UNIT COMPRISING A VALVE CAGE INCLUDING A VALVE SEAT ADAPTED TO BE MOUNTED IN SAID FUEL CHAMBER, SAID VALVE SEAT BEING PROVIDED WITH A CENTRAL APERTURE AND A PORT RADIALLY SPACED FROM SAID APERTURE, A VALVE RETAINER INCLUDING A TUBULAR STEM HAVING ONE END MOUNTED IN AND CLOSING SAID CENTRAL SEAT APERTURE AND AN ANNULAR SPRING SEAT PORTION ON THE OTHER END OF SAID STEM, A DISK VALVE SLIDABLY MOUNTED ON SAID STEM AND CLOSING SAID PORT, A COMPRESSION SPRING ENGAGED BETWEEN SAID SPRING SEAT PORTION AND SAID DISK VALVE, AN ANNULAR STRAINER FITTED COAXILLY ON SAID OTHER STEM END, SAID STRAINER HAVING AN OUTER PERIPHERAL FLANGE ADAPTED TO ENGAGE THE CYLINDRICAL FUEL PASSAGE, AND A TUBULAR EYELET PRESS-FITTED INTO SAID STEM AND CLAMPING THE INNER PERIPHERAL PORTION OF SAID STRAINER AGAINST SAID SPRING SEAT PORTION. 